Masuring performance and finding bottlenecks in PHP code?

[Marjeta]

Given a complex web site with a zillion of files, most of them including (or requiring) files, a ton of functions...
... is there a simple way to measure performance and find the slow functions (or blocks of code)?

Obviously I can add code to call time() at the beginning and end of each function, and subtract. But considering the number of functions that would take a very long time.

Is there something built in the PHP language or apache that could help me?

[Dormilich]

• APD PECL :: Package :: apd
• XDebug Xdebug - Debugger and Profiler Tool for PHP (available via PECL)
• DBG DBG | PHP Debugger and Profiler.

taken from a Zend Performance presentation